The shares of BP Plc continued falling on Thursday on concerns about the costs the British company will face in the massive Gulf of Mexico oil spill.

The shares opened trading in London 11 percent down before recovering to trade down 4.0 percent, one day after BP depositary shares plummeted to a 14-year low in New York.

President Barack Obama’s administration ratcheted up its demands on Wednesday that BP cover all the costs stemming from the disaster, including millions of dollars in salaries of workers laid off due to a drilling moratorium in the Gulf.

With polls showing public disapproval over Obama’s handling of the worst oil spill in U.S. history, the prospect of new government penalties has sapped investor confidence in BP.